Advanced high performance alloy materials are used in a variety of applications such as turbine components. The alloy materials are frequently made from Ni--Cr alloys, including alloys containing molybdenum and vanadium. These alloys find uses as turbine rotors and discs in both gas turbines and steam turbines. The turbine components are characterized by having a high yield strength to withstand the rigorous conditions during use. For instance, conventional base alloy materials used in steam and combustion turbine components have 0.2% yield strengths of from about 135 to about 155 ksi.
Imperfections sometimes result in the manufacture of the turbine components or result in the use of these components under operating conditions. The components must usually be replaced due to the unavailability of an adequate filler weld wire material that can provide a weld deposit having a comparable yield strength to that of the base metal.
Filler weld wire composition standards have been set by various testing societies. The American Welding Society has set forth various compositions in AWS A5.28 classes ER80, 90, 100, 110, and 120 that have 0.2% yield strengths of up to about 120 ksi. Commercially available filler weld wire compositions, such as those available from United States Welding Corporation contain from 0.09-0.11% wt. C, 1.8-2.0% wt. Mn, 0.3-0.4% wt Si, 0.002-0.005% wt. S, 0.9-1.05% wt. Cr, 2.2-2.4% wt. Ni, 0.55-0.7% wt. Mo, less than 0.005% wt. P, less than 0.01% wt. vanadium, and residual levels of other elements. However, the highest attainable 0.2% yield strengths with this material is up to 135 ksi.
There exists a need to develop a filler weld wire composition which has the strength characteristics comparable to the high performance base alloy materials. The filler wire composition should thus be able to provide a weld that has a comparable 0.2% yield strength to the base alloy while not compromising other physical characteristics below acceptable levels.